Smokeable planar or tubular-shaped food covering or film for food packagings, and method for the production thereof

ABSTRACT

The present invention proposes a smokable planar or hose-type food casing or food casing film for food packagings, such as, e.g., sausage casings, shrink bags or the like on polymer basis, which is for the first time manufactured in the jet-blasting process from a homogeneous molten plastic material consisting of a plastic mixture consisting of at least of PA (polyamide) with PVAL (polyvinyl alcohol) and PEBAX (polyether block amide). The food casing or food casing film has a water vapor permeability that is at least 1 kg/m 2  within 24 h. Its oxygen permeability at a film thickness of 30 μm is less than 2.1 cm 3 /m 2  within 24 h. Moreover the present invention for the first time proposes a method for manufacturing it.

The present invention relates to a smokable planar or hose-type foodcasing or food casing film for food packagings, such as, e.g., sausagecasings, shrink bags or the like on polymer basis as well as a methodfor manufacturing it.

Smokable sausage casings are known from practice and from literature.Thus DE 199 42 835 A1 teaches a sausage casing of an artificial sausagecasing material, for which purpose a gas and oxygen permeable, softplastic material is to be employed. The sausage casing materialdescribed in DE 199 42 835 A1 has an irregularly curved sausage shapewith welded longitudinal seams. This sausage casing is said to besmokable and have a sufficiently high strength for this purpose.

There is moreover known from DE 198 30 389 A1 a film for air-drying,smokable foodstuffs. Furthermore DE 101 25 762 A1 describes a shapedarticle having an irregular external contour, which is manufactured froma once-folded film material web of a weldable plastic in a welding andcutting machine for welding and separating the material webs. Thiscut-welded shaped article is said to result in a smokable sausage casinghaving a sufficiently high strength.

Moreover in DE 35 26 394 C2 a raw sausage casing is described which issaid to be produced of a binder-free spun fleece of at least onepolyamide joined together into a hose in the longitudinal direction.This raw sausage casing is said to be smokable. In DE 35 26 394 C2,reference is also made to DE 30 29 028 A1 that discloses a fiberfleece-reinforced artificial casing which is said to be smokable. Thefibre fleece used for this purpose may be formed on a polyamide base.Particularly suited spun fleeces are to be on the basis of polyamide andpolypropylene. The like spun fleeces are to be impregnated with acoating solution. Suitable coating materials in accordance with DE 30 29028 A1 are, in turn, any film-forming polymers that are applied in theform of a powder and subsequently thermally melted into a film orapplied as a coating in the form of a solution of molten material,suspension, or dispersion, and that may be formed into a film bysubsequent drying. Suited coating materials mentioned are, i. a.,molecular disperse or colloidal solutions or suspensions of variouspolymers by themselves or in mixtures, such as, e.g., polyvinyl alcohol.

DE 42 20 957 A1 finally discloses a packaging casing comprising aflexible carrier material provided with a foam layer. The coatingmaterial used for this purpose is to be fully saponified polyvinylalcohol. The foam of this substance is said to be waterproof,grease-tight and substantially impermeable for oxygen, nitrogen andcarbon dioxide. Merely water vapor may freely penetrate through the foamlayer of fully saponified polyvinyl alcohol. Fully saponified polyvinylalcohol is therefore said to be suited for sausage casings, inparticular for raw sausages. Furthermore combinations includingpolyvinyl alcohol with other plastic dispersions are said to beconceivable.

Smokable polyamide-based food casings with polyvinyl alcohol are thusknown from the prior art. These known smokable food casings must,however, revert to fiber fleeces or spun fleeces, nettings, or othercarrier or support materials, on which it is then possible to applycoatings. The like known smokable sausage casings can not bemanufactured on an industrial scale. They are moreover not suited forautomated further processing, e.g, in large butcher's shops, owing totheir low rigidity and thus low gathering suitability, and a dimensionalstability that is unsatisfactory as a general rule.

Accordingly it is an object of the present invention to propose asmokable planar or hose-type food casing or food casing film for foodpackagings which may cost-efficiently be produced in large amounts froma molten plastic material in industrial mass production, and which maysubsequently be further processed in an automated manner, as well as amethod suited for this purpose.

What is proposed is a smokable planar or hose-type food casing or foodcasing film for food packagings, such as, e.g., sausage casings, shrinkbags or the like, on polymer basis, which is for the first time formedin a jet-blasting process from a homogeneous molten plastic materialconsisting of a plastic mixture at least of PA (polyamide) with PVAL(polyvinyl alcohol) and PEBAX (polyether block amide). The plasticmixture preferably has a content of PA (polyamide) or of a mixture ofpolyamides of 40% (wt.) to 80% (wt.). The content of PVAL (polyvinylalcohol) is from 5% (wt.) to 40% (wt.), and the content of PEBAX(polyether block amide) is between 20% (wt.) and 30% (wt.).

Moreover the smokable food casing or food casing film produced in thejet-blasting process has a water vapor permeability of at least 1 kg/m²within 24 h. The oxygen permeability within 24 h at a film thickness of30 μm is less than 2.1 cm³/m².

Thus not only the large-scale industrial manufacture of smokable planaror hose-type food casings or films for food packagings is advantageouslyenabled for the first time in the jet-blasting process, but it ispossible to entirely do away with the nettings, flexible carriermaterials, or spun fleeces from the prior art that are felt to be aparticular drawback in large-series production, which particularly inthe case of fiber fleeces or spun fleeces moreover frequently had to becondensed or quite generally coated at increased complexity withoutbeing able to sufficiently increase their rigidity, which made gatheringvery difficult and in particular rendered gathering of small caliberssimply impossible without a netting. Accordingly, such known sausagecasings were not suited for automated further processing, and this hasnot changed to the present day.

In contrast, the smokable planar or hose-type food casing or food casingfilm according to the invention exhibits an excellent strength orrigidity and thus gathering suitability, and is thus for the first timesuited for automated further processing. Moreover it has at the sametime a good water permeability at a concurrently high oxygen barrier,even at extremely low film thicknesses, so that it is moreover for thefirst time possible to manufacture particularly thin films, which isfavorable for the subsequent smoking and optionally air-drying in thecase of hard sausages or salamis.

The smokable planar or hose-type food casing or food casing film inaccordance with the invention is characterized by a particularly goodgathering suitability allowing, even at small calibers having a diameterof less than 30 mm, a ratio of extended length to gathered length of atleast 100 m in the extended condition and 20 cm in the gatheredcondition. Moreover the casing or film in accordance with the inventionhas a very good dimensional stability, so that meat or sausage articlesthereby produced may particularly well preserve a desired shapepredetermined by the sausage casing after corresponding smoking steps,and optionally even after prolonged air-drying phases.

The extremely high oxygen barrier that may hereby be achieved, of lessthan 2.1 cm³/m² within 24 h even at a film thickness of no more than 30μm, not only results in a particularly good smokability of meat orsausage articles produced in such food casings or films in accordancewith the invention, but the food casing or food casing film inaccordance with the invention is at the same time particularly pliantand thus substantially better suited for automated processing, so thatit may not only be manufactured in large-series production, but maycorrespondingly also be employed well in large butcher's shops underlarge-scale industrial conditions. Furthermore the smokable food casingor food casing film in accordance with the invention is alsoparticularly well suited for raw sausages, such as, e.g., salami, andeven maintains contact without the formation wrinkles if the stuffingwas optionally, as an alternative, filled manually, i.e., withoutpressure or under only low pressure, i.e., without the use of dedicatedfilling machines.

The smokable planar or hose-type food casing or food casing film inaccordance with the invention may advantageously have film thicknessesof 10 μm to 50 μm, wherein it is particularly well possible in thejet-blasting process to produce film thicknesses of 20 μm to 40 μm atcalibers of up to 150 mm in diameter.

Meat or sausage articles produced with the smokable planar or hose-typefood casing or food casing film for food packagings in accordance withthe invention, such as, e.g., raw sausages and in particular salamis,lend themselves excellently for smoking and may be air-driedparticularly well.

The selected plastic mixture of 40% (wt.) to 80% (wt.) PA (polyamide),5% (wt.) to 40% (wt.) PVAL (polyvinyl alcohol) and 20% (wt.) to 30%(wt.) PEBAX (polyether block amide) for the first time allows theparticularly good manufacture of a smokable planar or hose-type foodcasing or food casing film in the jet-blasting process, which thus forthe first time satisfies all the requirements to a smokable sausagecasing, e.g., for hot dogs or for salami. Thanks to the sausage casingor foodstuff film a maximum water vapor and smoke permeability isattained, with particularly the smoke permeability being of importancefor the smoking process. At the same time a maximum possible rigidity isattained which is crucial for a good gathering process. The gooddimensional stability demanded for an optimum filling process is alsoobtained by this sausage casing or foodstuff film. Even the demanded lowadhesion of stuffing and the good peelability, that are influential forthe later processing processes, may readily be achieved with thefoodstuff film or sausage casing in accordance with the invention.Finally the desired high surface coloration of the sausage products thatmakes for the typical optical appearance of smoked sausage products isalso maintained with the foodstuff film or sausage casing in accordancewith the invention.

Various examinations and tests with the novel foodstuff film or sausagecasing revealed various trends. Thus, a high content of PA (polyamide)is essentially necessary for a good dimensional stability and rigidity.Nevertheless there is a tradeoff between the high content of PA(polyamide) and the desired smoke permeability, surface coloration, andadhesion of stuffing. Namely, a high content of PA (polyamide) reducesthe smoke permeability and the surface coloration and at the same timebrings about a possibly higher adhesion of stuffing than desired.

It was furthermore found that owing to the addition of PEBAX (polyetherblock amide), the water vapor and smoke permeability can be stronglyimproved and at the same time the peelability may be optimizeddecisively. Here it is, however, not possible yet to finally adjust thedesired high water vapor and smoke permeability solely by the additionof PEBAX (polyether block amide). Neither can the surface coloration yetbe adapted to full satisfaction solely by the addition of PEBAX(polyether block amide). Moreover the dimensional stability and therigidity may be degraded by faulty apportioning of PEBAX (polyetherblock amide), so that there is an additional tradeoff in this respect.

Here it was, however, surprisingly found that owing to the mixture ofPVAL or PVOH (polyvinyl alcohol) with PEBAX (polyether block amide) andPA (polyamide), it was for the first time possible to create a plasticmixture that results in the desired high water vapor and smokepermeability and furthermore ensures a high surface coloration at theselection and dosage, respectively, of the mixture constituents inaccordance with the invention. Moreover a substantially higher rigidityis obtained, and the adhesion of stuffing is further reduced. Thedimensional stability moreover maintains optimum adjustability with theplastic mixture of the invention.

Further advantageous developments and aspects of the invention resultfrom the features of the subclaims.

According to a preferred embodiment of the smokable food casing or foodcasing film for food packagings, the content of PA (polyamide) is from45 to 75% (wt.), preferably from 50 to 65% (wt.). The content of PVAL(polyvinyl alcohol) is between 10 and 35% (wt.), preferably between 15to 25% (wt.). Accordingly the content of PEBAX (polyether block amide)is from 23 to 27% (wt.), preferably from 24 to 26% (wt.). The mixingratios thus indicated result in a particularly good foodstuff film orsausage casing.

Thus it is provided in a preferred embodiment of the smokable foodcasing or food casing film for food packagings that its oxygenpermeability at a film thickness of 30 μm is in the range from 2.1cm³/m² to 1.0 cm³/m², preferably from 1.0 cm³/m² to 0.26 cm³/m², in aparticularly preferred manner less than 0.26 cm³/m² within 24 h.

In a further preferred embodiment it is provided that the water vaporpermeability is from at least 1 kg/m² to 100 kg/m², wherein in apreferred manner it is to be at least 10 kg/m² to 50 kg/M² and in aparticularly preferred manner between 20 kg/m² and 30 kg/m² within 24 h.

Furthermore it is provided that natural smoke or liquid smoke may beused for smoking. The casing or film of the invention may—depending onneed and purpose of use, as well as depending on the requirements duringthe subsequent processing steps—be manufactured while not drawn,unidirectionally drawn, or bidirectionally drawn. The casing or film ofthe invention may, according to wish, be in a monolayer or multilayerform.

The above discussed object is attained, in terms of method technology,wherein the above discussed advantages and aims may be attained in asynergetic manner.

The table represented hereinbelow contains excerpts from altogether 15preferred plastic mixtures successfully examined in in-house tests bythe applicant, with the mixing proportions being indicated in % (wt.).

No. PA 6.66 PVAL PEBAX 1 5033 FDX Mowiflex-L745 MH 1657 65% (wt.) 10%(wt.) 25% (wt.) 2 5033 FDX Mowiflex-L745 MH 1657 55% (wt.) 20% (wt.) 25%(wt.) 3 5033 FDX Mowiflex-L 745 MH 1657 50% (wt.) 25% (wt.) 25% (wt.) 45033 FDX Mowiflex-L 745 MH 1657 45% (wt.) 30% (wt.) 25% (wt.) 5 5033 FDXMowiflex-L 745 MH 1657 40% (wt.) 35% (wt.) 25% (wt.) 6 5033 FDXMowiflex-L745 MH 1657 60% (wt.) 18% (wt.) 22% (wt.) 7 5033 FDXMowiflex-L745 MH 1657 53% (wt.) 20% (wt.) 27% (wt.) 8 5033 FDX Mowiol8-88 MH 1657 55% (wt.) 20% (wt.) 25% (wt.) 9 5033 FDX Mowiol 8-88 MH1657 50% (wt.) 25% (wt.) 25% (wt.) 10 5033 FDX Mowiol 8-88 MH 1657 60%(wt.) 18% (wt.) 22% (wt.) 11 5033 FDX Mowiol 8-88 MH 1657 50% (wt.) 22%(wt.) 28% (wt.) 12 5033 FDX Poval OV 170 MH 1657 70% (wt.) 5% (wt.) 25%(wt.) 13 5033 FDX Poval OV 170 MH 1657 65% (wt.) 10% (wt.) 25% (wt.) 145033 FDX Poval OV 170 MH 1657 63% (wt.) 12% (wt.) 25% (wt.) 15 5033 FDXPoval OV 170 MH 1657 58% (wt.) 15% (wt.) 27% (wt.)

These preferred plastic mixtures and other ones were subjected to aplurality of in-house examinations and test series at the applicant's,in order to determine the plastic mixture (from which the film is thenmanufactured in the jet-blasting process from the molten plasticmaterial obtained therefrom) to be selected for optimum results for thesmokable planar or hose-type food casing or food casing film for foodpackagings in accordance with the invention, such as, e.g., sausagecasings, shrink bags or the like, and in order to be able to ascertainthe properties thereby achievable.

The above discussed aspects and advantages of the present invention maybest be obtained, while utilizing additional synergy effects, on anapparatus or plant of the present applicant for the manufacture ofhose-type food casings or food casing films for food packagings such as,e.g., sausage casings, in the jet-blasting process if additionally themeans for rapid cooling of thin thermoplastic hoses following theirextrusion as disclosed in the published patent application DE 199 16 428A1 to the present applicant is employed, or on the other hand thefurther development thereof in accordance with published patentapplication DE 100 48 178 A1. Here the hose-type film produced from themolten plastic material in the jet blasting head is subjected to intensecooling during which the amorphous structure of the thermoplasticmaterial from the molten plastic material is preserved. The hose-typefilm vertically extruded from the molten plastic material in the jetblasting head at first moves, without contacting the wall, into thecooling device for being cooled, as is described in detail in DE 199 16428 A1 as well as in DE 100 48 178 A1. Concerning details of thetechniques, the construction and the operation of this cooling means,also referred to as calibrating means, the contents of the disclosure ofDE 199 16 428 A1 and of DE 100 48 178 A1 are herewith fully incorporatedby way of reference in order to avoid repetitions. The hose-type filmthen passes inside the cooling means through supports against which thefilm supports itself due to a differential pressure between the insideof the hose-type film and the coolant, with a liquid film beingpreserved between film and supports, whereby adhesion of the hose-typefilm is precluded. The diameter of the supports has an influence on thediameter of the hose-type film, for which reason these cooling means bythe present applicant are also referred to as calibrating means. Theabove discussed aspects and advantages may be attained best by thecombination of the plastic mixture of polyamide with PVAL (polyvinylalcohol) and PEBAX (polyether block amide) with the jet-blasting processand the subsequent rapid, intense cooling by means of the presentlydiscussed calibrating means.

The present invention thus for the first time furnishes a smokableplanar or hose-type food casing or food casing film for food packagings,such as, e.g., sausage casings, shrink bags or the like on a polymerbasis, which may be manufactured in the jet-blasting process from ahomogeneous molten plastic material consisting of a mixture at least ofpolyamide with PVAL (polyvinyl alcohol) and PEBAX (polyether blockamide). The food casing or food casing film in accordance with theinvention for the first time exhibits a water vapor permeability that isat least 1 kg/m² within 24 h, and at the same time has an oxygenpermeability situated at <2.1 cm³/m² within 24 h at a film thickness of30 μm. Furthermore the present invention for the first proposes a methodfor manufacturing it.

1. A smokeable planar or hose-type food casing or food casing for foodpackagings, on a polymer basis, consisting of the smokeable food casingor food casing film is formed in the jet-blasting process fromhomogeneous molten plastic material consisting of a plastic mixture ofPA (polyamide) with polyvinyl alcohol and polyether block amide, whereinthe plastic mixture comprises a content of PA 9polyamide) or of amixture of polyamides of 40 to 75% (wt.), a content of polyvinyl alcoholof 5 to 40% (wt.), and a content of polyether block amide of 20 to 30%(wt.)
 2. The smokeable food casing or food casing film for foodpackagings in accordance with claim 1, wherein the content of PA(polyamide) is from 45 to 75% (wt.).
 3. The smokeable food casing orfood casing film for food packagings in accordance with claim 1, whereinthe content of polyvinyl alcohol is from 10 to 35% (wt.).
 4. Thesmokeable food casing or food casing film for food packagings inaccordance with claim 1, wherein the content of polyether block amide isfrom 23 to 27% (wt.).
 5. The smokeable food casing or food casing filmfor food packagings in accordance with claim 1, wherein it has a watervapor permeability that is at least 1 kg/m² within 24 h.
 6. Thesmokeable food casing or food casing film for food packagings inaccordance with claim 1, wherein it has a water vapor permeability thatis less than 100 kg/m² within 24 h.
 7. The smokeable food casing or foodcasing film for food packagings in accordance with claim 1,charactorized wherein it has a water vapor permeability within 24 h thatis at least 10 kg/m²to 50 kg/m².
 8. The smokeable food casing or foodcasing film for food packagings in accordance with claim 1, wherein ithas an oxygen permeability of less than 2.1 cm³/m² within 24 h at a filmthickness of 30 μm.
 9. The smokeable food casing or food casing film forfood packagings in accordance with claim 1, wherein it has an oxygenpermeability within 24 h at a film thickness of 30 μm in the range from2.1 cm³/mμ to 1.0 cmμ/m².
 10. The smokeable food casing or food casingfilm for food packagings in accordance claim 1, wherein the polyamidesare selected from a group comprising: polycaprolactame (PA 6),polyhexamethylene adipinamide (PA 66), PA 6/66, PA 11, PA 12, PA 6.12,PA 6/12, PA 6/69, MXD6 (modified polyamide 6), or mixtures of thesepolyamides or the like.
 11. The smokeable food casing or food casingfilm for food packagings in accordance with claim 1, wherein the casingor film is in a monolayer or multilayer form.